Background: Disturbed muscle balance in the hip joints of children with cerebral palsy (CP) shifts the pivoting point from the middle of the femoral head to the lesser trochanter. Forces that dislocate the femoral head progressively change acetabular shape, producing inadequate femoral head covering. The aim of the study was to carry out a radiological evaluation of hip congruency in children with CP after surgical treatment.
Material and methods: The study group consisted of CP patients operated on due to lower limb dysfunction between 1988 and 2001. All patients had undergone multilevel soft tissue release. A total of 52 children reported for follow-up examinations. There were 18 patients with hemiparesis (32%), 19 with diparesis (36%), and 15 with tetraparesis (29%). The age at surgery was between 2 and 19 y.o. (average age 7.33 y.o.). Radiological evaluation of the hip joints focused on changes in the migration index and the shaft-neck angle.
Results: The mean migration index before surgery was 30.4% in the group of diparetic and tetraparetic children. At the last follow-up examination, the average migration index was 32.5% on the right side and 25.6% on the left side (p>0.05). There was a statistically significant decrease in the value of the migration index in children operated on before the age of 8 years (p=0.007). In children operated on after the age of 8, the change in the migration index value did not exceed 0.5% (p>0.05).
Conclusions: 1. The mean migration index did not change significantly in the study group of surgically treated CP children. 2. Surgery had no influence on the shaft-neck angle 3. Surgery prevented progression of the migration index.